Somehow, but probably with the aid of caffeine said the self-professed coffee addict, Grohl carved out enough time to direct a documentary called Sound City based on the iconic San Fernando Valley-based Sound City Studios.

Despite the grotesque studio couch that was “rented for twelve years” and the dirty brown shag carpeting on the walls, Grohl joked that out of forty people he’s interviewed for the documentary, Mick Fleetwood is the only one who said the décor was great.

While the grungy little studio in Van Nuys didn’t have style going for it, the family-run Sound City Studios was reincarnated in the ‘90s as the place where great sounding records could be created all thanks to the immense success of a little album by Nirvana called Nevermind.

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Grohl said that when the record label asked Nirvana to record 1991’s Nevermind, they sent them to the then-expensive a $600-a-day “really cheap dump in the Valley” that also happened to house a gorgeous sounding, one-of-a-kind old analog Neve board and an exceptional organically-acoustic room. In the digital boom of the early ‘90s, finding that sort of rich, old-school sound was rare, but once Nevermind was released other bands like Rage Against The Machine, Tool, and Slipknot wanted to record their albums at Sound City Studios.

Imminent closure of the space was halted when business started booming and Grohl credits the studio with shaping the way modern music sounds now through the medium of Nevermind.

“Had we recorded that record in a different way,” Grohl elaborated, “The music wouldn’t have sounded the same. And if it didn’t sound the same, it might not have had the same impact.”

“The thing about that Neve board is that it has such a personality,” agreed Taylor, who recorded Iowa with Slipknot on that board. “No two albums sound the same coming out of that board because of the different love that you put into it, the different variables.”

In about a year, Grohl was able to rustle up interviews with over forty musicians, create an album and upcoming live show from the experience, and premiere his film at Sundance in Utah this coming Friday.

During the interview, Kevin & Bean played a collaboration track called “From Can’t To Can” from the Sound City film boasting the talents of Nielson, Scott Reeder from Kyuss on bass, and Taylor on beautiful, haunting vocals. Taylor said it all happened “effortlessly.”

“The movie is really mostly about the human element of music,” explained Grohl. “What it’s like to just get together with a person and write a song in a room in a day. It doesn’t have to be perfect but that’s how the magic happens. When you get four human beings playing with each other, you get the Beatles or the Rolling Stones. That’s where the magic happens.”

For the 12-12-12 concert for Sandy relief recently, Grohl performed a song he had jammed out prior with Beatle Paul McCartney. Entitled “Cut Me Some Slack,” the performance also featured surviving Nirvana members Novaselic and Smear. Grohl called McCartney “just the sweetest, nicest, most awesome person” and after they recorded some performances for the Sound City documentary, Grohl asked McCartney if he wanted to jam.

Grohl retold the day in McCartney’s quintessential Liverpudlian accent.

“We walked in; we jammed the song. It just came out of nowhere. The best songs happen that way,” said Grohl. “We recorded it live and put a vocal over it and that was it. It was three hours and it was perfect.”

Eight months after that experience, McCartney contacted Grohl to play the 12-12-12 show and because Foo Fighters were taking a break, McCartney suggests that Novoselic and Smear take their place. Without very much rehearsal, the performance was one of the most buzzed about sets of 2012.

“You have to understand, one of the great things about playing with Paul McCartney or playing with Neil Young is that that generation of musicians, they cherish and respect and value the practice of just going into a room and coming up with something and jamming and making it a song,” said Grohl. “There’s not like seven songwriters and seven producers and digital technology or whatever. It’s like people getting in a room.”

Which is exactly how Grohl and Taylor said they started their careers; basically, they failed (or in Taylor’s case became a burrito folding master) until their bands broke the sound barrier.

“All of us come from the same place,” said Grohl. “We were kids that bought instruments at a yard sale and then we started a band in a garage. We sucked and then we became the biggest band in the world. That’s how it happens. You don’t stand in line to be on a TV song contest show.”

“These old studios. There are so many stories,” said Grohl later, passionately tying all his personal experiences into the overall meaning of his Sound City documentary. “I really believe that the more depth you give a song, the more you can connect to it.”

“If you learn about the people and the story and the life behind these places where it was made and the relationship between them, it gives new meaning to music,” continued Grohl. “Because music should be more than just a sound. There’s emotion and there’s real human quality to music. Like music totally changed my life I would totally be smoking crack or dry walling, or whatever, or both, smoking drywall, if it weren’t for playing music.”

“The intention of the movie is really to inspire the next generation of kids to appreciate the simple human quality of music. You don’t have to do the TV show; you don’t have to be perfect. Pick up and guitar and suck and it’s the best feeling in the world until you become good and then you’re the biggest band in the world.”

The Hollywood Palladium show sold out within minutes this morning.

The Sound City documentary and soundtrack, Reel To Reel, are both available for pre-order now at soundcitymovie.com.